Continued: Brazilians angry at high cost of hosting World Cup protest in front of National Stadium

Police Col. Reinaldo Simoes Rossi, responsible for the officers policing the protest in Sao Paulo, said force was used only after demonstrators had altered an agreed upon route they marched along, instead moving toward main avenues in an attempt to halt traffic. He also said protesters hurled stones and other objects at police.

"Brazilian police must avoid excessive use of force," Atila Roque, director of Amnesty International's Brazil office said in a statement. "The increasing level of violence amid these protests is deeply troubling."

"Any excessive use of force beyond that permitted by law must be dealt with decisively by bringing those responsible to justice," he added.

Sao Paulo state Governor Geraldo Alckmin and Sao Paulo Mayor Fernando Haddad have said alleged uses of excessive force by police will be investigated.

Haddad has called for talks with protesters but said he would not negotiate a reduction transport fares.

The Free Pass Movement that organized the protest in Sao Paulo said on its Facebook page that a new demonstration will be held Monday.

"They want to shut us up, separate us and weaken us. But we won't let them. No one can deny us the right to protest until transport fares drop," the movement said.